GMC 4000 Series Service Manual page 305

Sec. 6B
Page 294
TORO-FLOW DIESEL ENGINE
DH478 TORO-FLOW DIESEL ENGINE TUNE-UP CHART
ENGINE MODEL ........................................... DH478
CYLINDER COMPRESSION (PSI) . . .
FIRING ORDER ..................................
VALVE LASH
Intake .........................................................
Exhaust ......................................................
GOVERNED SPEED (RPM)**
DH478 .........................................................
IDLE SPEED SETTING (R P M ).................
* With engine running at 625 rpm maximum variation between cylinders must not exceed 30 psi.
** Full load setting. (No load speed is approximately 200 rpm higher than full load speed.)
CONVENTIONAL MODELS WITH
TORO-FLOW DIESEL ENGINE
REMOVAL
1. Drain cooling system .
2. Disconnect battery.
3. If vehicle is equipped with air conditioning,
it is necessary to disconnect refrigerant lines
from condenser assembly which is mounted in
front of radiator.
CAUTION: Only personnel familiar
with air conditioning .service procedures
should attempt removal and/or instal I -
ation of air conditioning units.___________
4. Disconnect oil cooler lines from fittings at
radiator lower tank. Also disconnect radiator hoses
and heater hoses.
5. Remove front end sheet metal, referring to
SHEET METAL (SEC. 11) for necessary information.
6. Disconnect battery cable and wiring from
starter, remove engine ground strap, and discon­
nect wiring harness connections at generator, temp­
erature sending unit, etc.
7. Remove air cleaner and air inlet hoses.
Disconnect tachometer drive from engine and the
engine oil gauge pressure line. Disconnect engine
stop control and accelerator control linkage.
8. Disconnect air com pressor discharge line;
and when vehicle is equipped with power steering,
disconnect the power steering lines or remove
pump assembly from engine and allow pump and
lines to remain on ch assis.
9. Disconnect exhaust pipes from manifold.
Disconnect fuel supply and return lines.
10. Remove cover inside cab above transm is­
G M C S E R V I C E M A N U A L
FUEL INJECTION
500 (Min.)*
1 -6 -5 -4 -3 -2 INJECTION NOZZLE VALVE
FUEL SUPPLY PUMP OUTPUT
0.010"
0.018"
CYLINDER HEAD BOLT TORQUE
2800
FUEL OVERFLOW VALVE REGULATING
625-675
sion, then remove hand brake lever and transm is­
sion gearshift lever.
move control cross shaft.
transm ission. Also, remove road draft tube and
filter from rear of engine.
gine mounting bolts. Remove engine from chassis
with transm ission attached.
CLUTCHES (SEC. 7) of this manual, remove trans­
m ission and clutch from engine.
INSTALLATION
and install mountings referring to ENGINE MOUNT­
INGS (SEC. 6D) in this manual.
speedometer cable, install hand brake control link­
age,and gearshift lever. Install transm ission cover
and floor mat in cab.
stall road draft tube and filter (fig. 1) at rear of
engine.
connect throttle and engine stop control.
including engine ground strap.
manifolds.
Connect oil cooler lines.
TIMING ......................."INJ" Mark on Damper
OPENING PRESSURE (P S I).......................
MAXIMUM PRESSURE (P S I )..........................65
(FT.-LBS.) .............................................. 130-135
PRESSURE (PSI AT I D L E )....................
11. Disconnect clutch control rods and re­
12. Disconnect propeller shaft from rear of
13. Attach lifting equipment, then remove en­
14. Referring to the TRANSMISSIONS AND
1. Assemble clutch and transm ission to engine.
2. Hoist power plant into position in chassis
3. At transmission, connect propeller shaft,
4. Connect and adjust clutch control. Also, in­
5. Connect tachometer drive (when used), and
6. Connect fuel supply and return lines.
7. Connect exhaust pipes to manifolds.
8. Connect electrical wiring and starter cables
9. Install air cleaner and hoses to intake
10. Install accessories and adjust drive belts.
11. Install front end sheet metal and radiator.
3000
18-28